On Thu, Jun 9, 2011 at 11:46 PM, Andreas Fritiofson
<andreas.fritiofson at gmail.com
<https://lists.berlios.de/mailman/listinfo/openocd-development>> wrote:
>/ Setting the FTDI pins to Hi-Z is not necessarily the same as setting the
/>/ pins in the JTAG connector to Hi-Z. There is arbitrary dongle-specific
/>/ interface logic between the FTDI chip and the connector.
/
Not true. Good example here can be KT-LINK SWD+JTAG buffers [1]
configuration designed by Krzyszfot Kajstura - all signals can be
electrically disconnected from target and they are in default
configuration (after powerup). This is really nice design, also the
first open SWD+JTAG for FT2232H chip. Interface can also offer
additional signals such as various resets and control that also should
be disconnected, especially for other transports. Upcoming SWD
framework make use of existing ft2232 code, also the ft2232_quit()
function, so there is a default possible behavior common to all
ft*232-based devices. Thats not that complicated, isn't it?
[1]
http://sourceforge.net/apps/mediawiki/stm32primer2swd/index.php?title=File:Ktlink-buffers.png
Best regards,
Tomek
You say "Not True" and you refer to a specific dongle layout ? Strange.
For our Amontec JTAGkey, putting all FT2232 Channel A in HIGH-Z during
MPSSE will be enough as the KT, but it will be much stronger if we have
specific deinit function for each layout, as we have a specific init
function for each layout ...
Regards,
Laurent
http://www.amontec.com/jtagkey.shtml
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